The notion of an international legal system

This chapter identifies the different notions of an international legal system that are entailed by legal positivism, legal idealism and legal realism. For legal positivists, a legal system consists of legal norms organized according to the way in which they confer authority upon each other. The relation between norms remains conditioned only by the pedigree of norms and their logical form. For legal idealists, a legal system consists of legal norms and one or several ideals set for the legal project. The relationship between a legal norm and a presupposed legal ideal is a matter of the efficacy of the norm relative to this ideal. The relationship between the legal norms among themselves is a matter concerning the degree to which norms help to bring about this same ideal. For legal realists, law is everything that figures in a prediction of how legal decision-makers in a jurisdiction would generally decide. This includes legal culture; it includes the social facts, which a legal culture urges legal decision-makers to consider, and which, for this reason, potentially, serve to influence legal decision-making. The relationship between these different elements of international law is one of cause and effect. For legal realists, if we can ever think about international law as a system, then this is because, in the light of legal culture, some social facts are the predictable cause of future legal decisions.